Stuart Lancaster has reacted to allegations that referee Nigel Owens was the subject of homophobic abuse at Twickenham by warning fans that such behaviour has no place in the game.

The Rugby Football Union is probing the claims made in a letter written to a national newspaper by a spectator who attended the 24-21 defeat by New Zealand in last Saturday's opening QBE International.

"I could not believe that a bunch of men half my age watching a rugby match in the 21st century could be capable of hurling such nasty, foul-mouthed, racist, homophobic abuse at an openly gay match official," read the letter published in The Guardian.

While the RFU stresses that allegations of abuse of any type at Twickenham are extremely rare, it states that it is taking the matter "very seriously".

Owens has called for bans to be issued if the claims are proven and Lancaster has issued a reminder of the conduct expected of England supporters.

"I'm aware there's an investigation going on and rightly so. We applaud the stance the RFU are taking and the investigation," Lancaster said.

"We've worked hard in rugby to get the core values of the sport ingrained in the team and in rugby in general, so there is no place for this whatsoever.

"Certainly having met Nigel on Friday we wanted him to have an enjoyable experience coming to England and it's a shame if he feels that memory has been tarnished by the allegation.

"We have got to understand the pressures that people are under and be supportive. That is all we want to achieve with referees."

Lancaster has repeatedly called on England fans to play their role in turning Twickenham into a fortress knowing all but three matches of their knockout phase of next year's World Cup are being staged at the venue.

But the 45-year-old insists the distinction between passionate support and abusive behaviour is easy to draw.

"Generally you want a crowd that is behind the team but respecting the core values of the sport," Lancaster said.

"That balance should be easily achieved. That is what we feel the crowd give us - a huge amount of energy."

New Zealand's performance of the Haka on Saturday was drowned out by a rendition of 'Swing Low, Sweet Chariot', but Lancaster is satisfied this did not cross any boundaries.

"I don't think the crowd are being disrespectful by singing 'Swing Low' during the Haka," he said.

"The crowd was responding to a challenge and there is a difference, as long as the crowd shows respect.

"I go back to the core values of what we are about. One of the key core values is respect.

"We need to show that as a team and as a country to all opposition players, coaches, referees and opposition spectators as well."

Decisions made by referees are under greater scrutiny than ever before due to replays of key incidents being shown on the big screen at grounds, creating the potential for officials to be abused.

On Saturday Owens awarded a controversial first-half try to New Zealand fly-half Aaron Cruden without consulting the TMO and loud boos from the 82,223 crowd greeted the try when it was repeatedly televised.

All Blacks head coach Steve Hansen was aggrieved at the extensive use of replays at Twickenham, but his anger was directed at TV producers who he insists are "starting to have an influence on the game" because of the footage they opt to show.

"Generally there are more screens in stadiums now and more decisions that get replayed on screens," Lancaster said.

"In the recent game between South Africa and New Zealand there was an incident constantly replayed. (Referee) Wayne Barnes' attention was drawn to it, so he went back to look and it was a penalty.

"It is more for debate at a higher level about the rights and wrongs of that. I don't have any input at the moment. In football they don't allow it at all."

RFU chief executive Ian Ritchie has confirmed that action will be taken if the allegations are proven.

"The RFU condemns all forms of discrimination," Ritchie said.

"We aim to ensure that everyone has the opportunity to enjoy rugby in an environment free from all prejudices and in line with rugby's core values: teamwork, respect, enjoyment, discipline and sportsmanship.

"We take any allegations of abuse very seriously and are investigating the matter. If we find sufficient evidence we will of course take action."